• Requirement: Construct any dwelling unit on levels one through four above grade with radon-resistant construction techniques. Follow the techniques prescribed in EPA Building Radon Out; NFPA 5000, Chapter 49; International Residential Code, Appendix F; CABO, Appendix F; ASTM E1465; or a local equivalent, whichever is more stringent.

How is this interpreted for a 10 story multi-family building? What specifically is required for floors 2-4? I am not sure what is being conveyed about construction in particular for floors 2-4. Or does this mean if a mixed use building has retail floor one and residential above, floor 1 still requires radon resistant construction [gas collection, venting pipes and an outlet for future fan installation].  Thanks!